This invention relates to devices and methods for housing and protecting well heads, particularly for housing and protecting the heads of environmental monitoring wells while permitting convenient access thereto.
It has become a common practice to install monitoring wells in the ground in areas where the ground water is at risk of contamination. Such wells, known as environmental monitoring wells, are typically installed, for example, around the periphery of solid waste landfills or where there has been, or there is a potential for, a hazardous or toxic chemical spill. Water is periodically extracted from the wells and tested for the presence of contaminants.
Basically, environmental monitoring wells are just pipes installed vertically in the ground, extending to various depths and terminating at a well head near the surface of the ground. Typically, there is no substantial permanent equipment located at the well head; it is simply capped between usages. In some cases there may be a small monitoring device installed at the well head. There is ordinarily no attendant at the well head; it is only visited periodically to extract water for tests or, in some cases, to check a small monitoring device.
There is a risk that an environmental monitoring well can itself become a source of contaminants. This will happen if surface water containing contaminants, or an undiluted contaminant itself, is allowed to enter the well pipe. This can occur, for example, if there is uncontainedsurface water adjacent the well head at the time that it is uncapped for testing, or where the cap is not adequately sealed. It can also occur where part of the well head protrudes above the surface of the ground and is damaged by the movement of vehicles or heavy equipment, leaving the interior of the well pipe exposed in a manner that permits the introduction of contaminants. It is important to ensure that this does not occur.
In order to minimize the likelihood that environmental monitoring wells will contaminate the very water they are installed to test, it is desirable, if not required, to provide them with a fluid resistant housing in addition to the well cap itself; indeed it is desirable to provide a housing that is impervious to water and other fluids, i.e., fluid-tight. Known housings typically extend above the surface of the ground and provide a cover that is less than fluid-tight. For example, Ames et al. U.S. Pat. No. 4,669,536 discloses a protective housing disposed around the end of a monitoring well pipe, set in concrete and having a hinged cover on top. But, the housing extends above the surface of the ground where it can interfere with, and be damaged by, the movement of vehicles and equipment. There is no provision for making the hinged cap fluid-tight.
In addition, various types of caps are available for sealing pipes in general. Delahanty U.S. Pat. No. 759,081 shows a cap which, together with a gasket, is fastened to the end of a pipe by bolts. Baker et al. U.S. Pat. No. 3,473,573 and Forsburg U.S. Pat. No. 1,509,643 disclose well caps which are also fastened with bolts and include gaskets. Rooney U.S. Pat. No. 3,856,050 and Richardson U.S. Pat. No. 3,942,681 show flange protectors for placement over the ends of flanged pipes. However, none of these devices is, or could readily be, adapted to provide a fluid-tight cover for an environmental monitoring well that is in addition to the well pipe cap itself and is flush with the ground.
It has also been found that frost can dislodge a well housing, thereby breaking the seal and opening the well bore to contamination. When the environmental monitoring well is located in a location accessed or accessible by the public, there is a need for a well head housing that is resistant to tampering or vandalism by unauthorized personnel. Such actions can also destroy the integrity of the housing and allow contaminants to enter the well bore.
Therefore, it can be seen that there is a need for a new and improved environmental well housing that minimizes the risk of contamination of the ground water which the well is installed to monitor.